Gelatin Veronal Bufferer (GVB)

Specifications

• Name: GVB (without Ca++ and Mg++)
• Composition: 0.1 % gelatin, 5 mM Veronal, 145 mM NaCl, 0.025 % NaN3, pH 7.3.
• Form: Liquid
• Preservative: Sterile filtered with 0.025% sodium azide as a bactericidal agent
• Storage: +4oC. Avoid freezing which causes gelatin to gel. If frozen, do not microwave or heat the buffer on a hot plate instead heat the buffer in a water bath at 100 oC to redissolve gelatin.
• Precautions: Azide is poisonous to all living organisms.

Detailed description

General Description

GVB is a basic buffer that can be used to make other traditional buffers used for complement assays. Ca++ and Mg++ may be added to GVB to make GVB++ for classical pathway and lectin pathway assays. MgEGTA may be added to GVB for alternative pathway assays. EDTA may be added to GVB to prepare GVBE to inhibit complement activation. GVB is also used for dilution of serum and other assay components in many complement assays especially in alternative pathway assays.

Buffer Components

Veronal is used as the buffer because in the mid-1900s this was the only buffer for pH range 7.2-7.4 that did not chelate metal ions and did not to inhibit complement reactions as did other buffers. Sodium chloride is present to provide an isotonic environment so that cells do not lyse due to osmotic pressure. Gelatin is present to prevent loss of protein components due to adsorption onto tips or tubes during dilutions and in the assays themselves. Azide is present to prevent bacterial growth.

Physical Characteristics

The concentration of gelatin in this buffer is below the concentration that forms solid gels. However, because of the gelatin is close to its gelling concentration at 4oC some strings of gelatin form during standing at this temperature. They can be redissolved easily by heating to 37oC or by brief heating in a microwave oven.

Applications

GVB should be used to prepare Er and to wash them before their use in assays. GVB is used to dilute all of the components of alternative pathway assays. The General Description section above describes the use of GVB to prepare GVB++, MgEGTA for alternative pathway assays and EDTA to prepare GVBE. GVB is also used for dilution of serum and other assay components in many complement assays especially in alternative pathway assays.